Such dispensers generally comprise a mandrel which is removably mounted between two relatively fixed cheeks to support a roll of sheet material (referred to hereinafter, for convenience, as tinfoil) as well as a serrated blade parallel to the mandrel enabling a section of tinfoil to be cut off. The maximum length of the tinfoil roll is determined by the length of the mandrel and the spacing of the cheeks.
In order to allow the use of rolls of different lengths, not exceeding that maximum, it has already been proposed to provide the mandrel with an adjustable collar which can be axially shifted thereon and has an outer diameter exceeding the inner diameter of the tinfoil roll, thereby serving as a stop for the latter. If that collar is held against rotation in a selected axial position, it may exert an undesirable braking effect upon the roll inasmuch as its convolutions of larger diameter will tend to shift sideways so as to envelop that collar.